Metal treating furnace



May 24, 1932.

C. T. WILLARD ET AL METAL TREATING FURNACE a d W W .W m .1 a m K W J a m w 3 win h v w 7 m j J F NN l mw i2 f I 15 N y 1932- c. T. WILLARD ETAL 1,860,065

' METAL TREATING FURNACE I Filed Nov. 25, 1930 4 Sheets-Sheet 2 gwuehtow CkarZes Z Willard and Ric/Lard Kaier W LMM:

May 24, 1932.

c. T. WILLARD ET AL 1,860,065

METAL TREATING FURNACE Filed Nov. 25, 1930 4 Sheets-Sheet 3 May 24, 1932- c. T. WILLARD ET AL I METAL TREATING FURNACE 4 Sheets-Sheet 4 Filed Nov. 25, 1930 MnHHHHHHHHHHhHH HHHHHHHHHIMHHHHHHHI PHH ammo Rickard Kaz'er Patented May 24, 1932 CHARLES r. WILLARD, or ROSELLE, am; Morin ma, or c'aanrozap, NEW JEY,

ASSIGNOBS TO THE smenn MANUFACTURING comrm, or amzarn'rn, NEW ma- SEY, A. CORPORATION OF JERSEY manner. TREATING rummcn This invention relates to a metal treating Y furnace and has for an object to provide a furnace equipment suitable for the heating of metal'parts to any desired temperature in any desired atmosphere while said parts are being carried through the furnaceon a conve or passing into and out of-the latter.

ore specifically, the invention has for an object to provide an improved continuously operable furnace equipment suitable for the scale-free hardening of steel parts.

With the above and other objects in view,

as will hereinafter appear, the invention comprises the devices, combmations and arrangements of parts hereinafter described and claimed;

' The features of the invention and the advantages attained thereby will be readily understoodby those skilled in the art from the following detailed description of a preferred embodiment of the invention taken in connection with the accompanying drawings, in which Fig. 1 is a longitudinal vertical section through the furnace. Fig. 2 is a plan view of a fragment of the conveyor-belt. Fig. 3 is a sectional view on the line 3-3, Fig; 2. Fig. 4 is a horizontal section through the furnace. Fig. 5 is a front end elevation of the furnace with the loading platform in section on the line 55, Fig. 1. Fig. 6 is'a transverse vertical section through the furnace on the line 66, Fi 1. Fig. 7 is a section on the line 7 7, ig. 1. Fig. 8 is a plan view of one of aspair of tractor-belt members of the conveyor driving mechanism. Fig. 9 is a section through the tractor-belt shown in Fig. 8, and 10 is a rear end elevation of thefurnace on a reduced scale, showing the quench ing tank in vertical longitudinal section.

1 represents an elongated box-like heating chamber of refractory heat-insulating material supported on le s 2 and heated internally by suitable gasurners 3. Supported Within the furnace on stilts 4 is the flat rectangular taubular retort 5 including the tight cover 6. The receiving end-7 of the retort extends out through the front wall of thefurnace chamber 1 and the rear end 8 of the retort is continued throughthe rear end wall of the furnace chamber 1 where it is tightly closed by a removable cover plate 9 which may be fitted with a sight-cock 9 through which the interior of the retort 5 may be observed under working conditions.

The bottom wall of the retort 5 is formed at the delivery end of the latter with an opening from which extends downwardly a vertical passageway 10 the lower end of which dips below the surface of, and is sealed by, a quenching bath 11 of oil or-other suitable liquid in the quenching tank 12. The lower end of the "wall of the passageway 10 is formed with cut-outs 13 the upper edges 14 of which are positioned but slightly below the constant oil level of the quenching bath 11 for a purpose to be explained. Extending.

downwardly and forwardly from the front wall of the vertical passageway 10 is an inclined branch passageway 15" leading to a tightly closed pulley-box 16 from which the passageway 17 leads to a conveyor-seal 18.

A loading or receiving platform 19 is connected to the receiving end 7 of the retort and rests upon supporting rolls 20 carried ?5 by the suitable supported angle-irons 21. The bottom wall of the loading platform 19 is even and continuous with the bottom wall of the retort 5. p

A conveyor-belt 22, preferably ofwoven wire such as shown; in Figs. 2 and 3, passes over the loading platform 19 and through the retort 5 to the discharge passageway 10 where it passes downwardly over the pulley 23 and seal, the conveyor-belt 22 passes over the pulthroughthe inclined branchpassageway 15 8 which access may be had to the ley 25 and then dips into the water or liquid 26 and passes under the submerged pulley 27 from which it emerges from the liquid 26 and passes over the pulley 28 to the conveyor driving mechanism A from which it passes upwardly and over the pulley 29 to the receiving platform 19 in an endless circuit.

The conveyor-seal 18 consists of an opentopped tank in which the pulley-rolls 25, 27 and 28 are journaled, as shown in Fig. 1. T he bottom wall of the passageway 17 joins one end wall of the tank 18 and the upper wall of the passageway 17 is extended downwardly at 17 and caused to dip below the surface 26 of the liquid in the tank 18.

It will be understood that when the furnace is in operation say for scale-free hardening, a suitable non-oxidizing gas, such as ordinary illuminating gas, is admitted to the retort 5 through the gas-inlet 30. The gas fills the retort 5 and passageways 10, 15, 16 and 17, but can escape from none of these as they are all substantially gas-tight. A flow of gas, indicated by the arrow in the retort in Fig. 1, is maintained toward the mouth of the retort, counter to the direction of movement of the work, to prevent the entrance of air to the retort. The gas escaping from the mouth of the retort may conveniently be disposed of by being burned at 31.

The pulley-box 16 is provided with cleanout openings 34 closed by suitable covers 35. A removable cover-plate 36 is also provided to close the aperture 37 in the wall 17 through ulley-roll 25.

The conveyor-driving device is constructed with a frame 38 formed-of angle-irons and carrying bearings 39 for the upperand lower pairs of sprocket-shafts 40 to which are fixed the sprockets 41 connected by the upper and lower pairs of sprocket-chains 42.- The sprocket-chains 42 of each pair are connected by the transverse slats 43 which, together with the chains 42, constitute two endless tractorbelts, the lower of which runs over the stationary rests 44 and the upper of which runs under the spring-pressed presser-bars 45 and is pressed downwardly into operative gripping engagement with the conveyor-belt 22 upon the slats 43 of the lower belt.

The resser-bars 45 are fixed to the transverse supporting bars 46 to the ends of which are fixed the vertical rods 47 slidably mounted in the angle-irons 48, Fig.v 5, and pressed downwardly by the springs 49. One eachof the upper and lower shafts 40 are connected together by a pair of spur gears 40 and one of the upper shafts 40 carries a sprocket 50 by which the entire conveyor-driving mechanism A is operated from a driving chain 51, Fig. 4, receiving power from the output shaft 52 of a standard speed-reducer 53 the input shaft 54 of which carries a belt-pulley 55 and is driven by the belt 56 from the output shaft 57 of a second standard adjustable form of speed-reducer 58, the input shaft 59 of which is driven by the electric motor 60. By means of the driving mechanism described, the necessary traction may be applied to the conveyor-belt 22 to move the latter without slippage or injury, even though it be heavily loaded.

In the operation of the furnace, the parts to be treated are placed upon the conveyor 22 at the loading platform 19 from which they pass through the flame 31 and into the retort 5 where they are heated up to the requisite temperature in an oxygen-free atmosphere. When the work-pieces pass over the roller 23 they fall downwardly through the vertical passageway 10, still in an oxygenfree atmosphere, and into the quenching bath 11 in the tank 12 from which they are removed by a suitable canvas conveyor-belt 61 reinforced by transverse strips 62. The main conveyor-belt 22 does not enter the quenching bath 11 but passes downwardly through the branch passageways 15 and 17 from which the outside air is excluded, as previously described.

The hot articles falling into the quenching bath 11 soon heat the upper layers of the latter and generate a certain amount of vapor within the submerged lower end of the passageway 10. The cut-outs 13 are provided for the circulation and escape of these heated upper layers from the submerged lower end of the passageway 10; the upper edges 14 of the cut-outs 13being maintained only a slight distance below the constant level of the surface of the quenching bath. A vapor exhaust outlet pipe 1O is connected between the lower end of the passageway 10 and the retort 5 proper. HA suitable suction is ap plied to the pipe 10 generated at the surface of the bath prevent such vapors from rising into the retort through the passageway 10. Where an oil quenching bath is used, the hot oil vapors, if not disposed of, might cause a sooty deposit on .the work.

There is disposed alongside the quenching tank 12, a sump-tank 11 which receives oil passing out of the quenching tank 12 through the overflow 11". The provision of the overflow 11 insures maintenance of a constant oil-level slightly above the upper edges 14 of the cut-outs 13. It is understood that the oil is to be continuously pumped out of the sump-tank 11' and through suitable cooling coils (not shown) and returned to the quenching tank 12. The furnace is thus adapted for continuous operation and will produce hardened steel articles which are, for all practical purposes, as bright in color and free from scale as when they entered the furnace. In starting up the furnace, gas may be admitted through the'pipe 36 to purge the Various passageways of air, after to remove any vapors 11 and which the flow of gas through the pipe 36' sole application of Richard Kaier, Serial No.

498,101 filed herewith.

The invention is not to be understood as limited to its use for hardening steel parts as it is obviously adapted broadly for continuously processing metal parts in any desired atmosphere at'any desired temperature.

Having thus set forth the nature of the invention, .what we claim herein is 1. A metal treating furnace comprising a gas-tight retort having an open receiving end and a delivery end, a loading platform in advance of said open receiving end, a quenching. bath in gas-tight communication with said delivery end, means for maintaining a flow of gas within said retort toward said receiving end, and an endless belt-conveyor passing through and out of said retort to the external atmosphere and over said loading latform into said open receiving end.

horizontally disposed retort having an open 2. A furnace having a heated retort, said retort having an openreceiving end and a delivery end, a liquid seal at the delivery end of said retort, a branch passageway leading from said retort above said liquid seal, an endless conveyor passing through said retort and out through said branch passageway, a conveyor seal at the end of said branch passageway, a loading platform in advance of the open end of said retort over which said conveyor runs, and means for maintaining a flow of gas within and toward the open receiving end of said retort.

3. A metal treating furnace comprising a receivin end and a delivery end, a quenching tank at t e delivery end of said retort, a, workdischarge passageway, extending from said retort to said quenching tank, a liquid seal at the lower end of said ,work-discharge passageway, a branch passageway leading from one side of said work discharge passageway, an endless conveyor-belt passing through said retort and out through said branch passageway, a conveyor-seal at the end of said branch passageway from which the conveyor-belt emerges to the outside atmosphere, and means applied to the portion of said conveyor-belt in the outside atmosphere for pulling the latter through said retort.

4. A metal treating furnace comprising a tubular retort having an open receiving end and formed at its deliver end with main and branch passageways, Independent seals at the ends of said passageways-an endless belt-conveyor passing through said retort and out of the latter to the external atmosphere through the seal at the end of said branch passageway, a quenching tank into which the at one en adjacent its opposite end, an endless beltwork is discharged through said main passageway, means for maintaining a flow of gas within and toward the receiving end of said retort, and conveyor driving means operating upon that portion. of the belt-conveyor to said quenching tank, a belt-conveyor passing through said retort and downwardly through said opening, a gasi-tight'conveyor passageway branching from said work-discharge passageway above said quenching tank, and a heating chamber substantially enveloping said retort and work-discharge opening.

6. A furnace having a closed horizontal heating chamber constructed with an inlet and an outlet in its bottom wall conveyor having an upper run passing through said chamber and a return run disposed below said chamber, a gas-tight conveyor passageway connected to the outletof said heating chamber, a seal at the end of said conveyor passageway. through which said conveyor emerges to the outside atmosphere, and work-cooling means in gas-tight com.- munication with the outlet of said heating chamber and spaced from said seaL' 7. A furnace having a heating chamber formed at its delivery end with a downwardly extending gas-tight work-discharge passageway, and a liquid quenching tank into which the lower end of said passageway dips, the side walls of said passageway having cut-away portions below the level of the liquid in the quenching tank, said cut-away portions permitting circulation of hot liquid away from the space within the submerged lower end of said passageway.

8. A metal treating furnace having a laterally closed, heated, tubular retort disposed substantially horizontally and having a receiving mouth at one end and a discharge opening adjacent-its opposite end, a quenching tank containing. a quenching liquid in gas-tight communication with said discharge opening, means for feeding work throu h said retort, and means for supplying a e sired gas to said retort in such manner as to maintain a continuous flow of gas toward the mouth of said-retort. 9. A metal treating furnace includin a tubular retort having at its delivery end a work-discharge opening, a quenching bath in gas-tight communication with said opening,

quenching bath. v r

l0. A metal treating furnace including a,'

are

substantially horizontal tubular retort havw an open receiving end and a discharge is in its bottom Wall at its discharge nenching bath dispos helm-J said opening and in gas 1' miion 'th the latter, means to said retort intermedime ii a vapor exhaust means between said. discharge opening and said quenching bath. In "iesdmony whereof we have signed our names to this specification.

CHARLES T. WILLARD.

RICHARD KAIER. 

